Reverting the incremental GC in Python 3.14 and 3.15

Python's core development team has decided to revert the incremental garbage collector introduced in Python 3.14, reverting both 3.14 and 3.15 back to the generational GC from 3.13. The decision was driven by reports of significant memory pressure in production environments. The incremental GC also bypassed the PEP process and had previously been rolled back before 3.13's final release. For 3.14, an early patch release (3.14.5) will ship the revert; for 3.15 (still in alpha), an extra alpha release may be issued. If the incremental GC is to be reintroduced in 3.16, it must go through the formal PEP process for thorough evaluation.